Connector for stick

ABSTRACT

A locking mechanism for poles includes a support rod, inserted into a first unit shaft at a first end thereof and locked to a second unit shaft at a second end thereof, with threads formed around the outer circumferential surface thereof; and a pressure locking unit movably engaged with the threads of the support rod and having longitudinal slits formed to open in one direction and at least two pressure parts formed in a longitudinal direction. The locking pressure of the pressure locking unit is imposed on the unit shafts at multiple longitudinally spaced points, thus dispersing or distributing the locking strength in the longitudinal direction and increasing both the locking strength and the resistance against both longitudinal compressive force and longitudinal tensile force, thereby preventing the locked unit shafts from suddenly slipping towards each other.

TECHNICAL FIELD

The present invention relates, in general, to locking mechanisms forpoles and, more particularly, to a locking mechanism for poles, whichreleasably locks a plurality of unit shafts of a pole to each other.

BACKGROUND ART

Generally, poles are long thin pieces that may be used for variouspurposes, such as walking sticks for hiking or trekking or support polesfor tents.

Such poles are typically used by aged people, physically handicappedpeople, hikers and trekkers. Further, poles may be used as a symbol ofdignity or for self-protection by some people. Thus, such poles may becalled walking sticks, staffs or canes.

In recent years, the structures of poles have been developed such thatthe poles comprise a plurality of assemblable unit shafts instead of anintegrated single shaft having a fixed length. Thus, the assemblablepoles proposed in recent years can be conveniently stored when not usedand the lengths thereof can be easily adjusted as desired.

The conventional poles having the assemblable structures are configuredto realize locking between neighboring unit shafts thereof on onesurface (that is, one surface locking), so that the poles can somewhatefficiently resist compressive force. However, when tensile force isapplied to the pole by pulling two locked unit shafts from each other inopposite directions, both the frictional force and the locking strengthbetween the two locked unit shafts are reduced, so that slippage mayoccur between the two locked unit shafts and the locked state betweenthe two unit shafts may be released, thus sometimes subjecting users tosafety hazards.

DISCLOSURE OF INVENTION Technical Problem

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the related art, and is intended to providea locking mechanism for poles, which increases the locking strength oflocked unit shafts of a pole, thus realizing improved utility andimproved quality of the poles.

Technical Solution

In order to accomplish the above object, the present invention providesa locking mechanism for poles, comprising: a support rod inserted into afirst unit shaft at a first end thereof and locked to a second unitshaft at a second end thereof, with threads formed around part of anouter circumferential surface of the support rod; and a pressure lockingunit movably engaged with the threads of the support rod throughscrew-type engagement, with at least one pair of longitudinal slitsformed in the pressure locking body such that the slits are open in onedirection, and with two or more pressure parts formed in the pressurelocking body in a longitudinal direction.

In an aspect, the pressure locking unit may comprise a pressure lockingbody, the pressure locking body comprising: an annular-shaped firstpressure part provided around an edge of a first end of the pressurelocking body; and an annular-shaped second pressure part formed by apressure protrusion formed around an outer circumferential surface ofthe pressure locking body, and the support rod may comprise a taperedshoulder part at a predetermined location near the threads, wherein thepressure locking body is provided on an inner circumferential surfacethereof with a tapered seat part so as to correspond to the taperedshoulder part of the support rod.

In another aspect, the pressure locking unit may comprise a pressurelocking body having a pair of first slits and a pair of second slits,which are formed in the pressure locking body such that the first andsecond slits are angularly spaced apart from each other at right angles,wherein the pressure locking body comprises: an annular-shaped firstpressure part formed around a first edge of the pressure locking bodyand an annular-shaped second pressure part spaced apart from the firstpressure part; and an annular-shaped third pressure part formed around asecond edge of the pressure locking body and an annular-shaped fourthpressure part spaced apart from the third pressure part, wherein thefirst and second slits are opened in opposite directions, the supportrod is provided both with a first tapered shoulder part at a locationnear a first end of the threads and with a second tapered shoulder partat a location near a second end of the threads, and the pressure lockingbody is provided on an inner circumferential surface thereof with atapered seat part so as to correspond to the first tapered shoulder partof the support rod.

In a further aspect, the pressure locking unit may comprise: a firstpressure locking body having both at least one pair of slits and anannular-shaped first pressure part formed around an edge of the firstpressure locking body; and a second pressure locking body having both atleast one pair of slits and an annular-shaped second pressure partformed around an edge of the second pressure locking body.

In yet another aspect, the support rod may comprise: first threadsformed around an outer circumferential surface of the support rod; atapered shoulder part formed around the support rod at a location abovethe first threads; and second threads formed around the support rod at alocation above the tapered shoulder part and having a diameter less thanthat of the first threads, wherein the first pressure locking body ismovably engaged with the second threads of the support rod throughscrew-type engagement, the support rod is provided on the second threadswith a wedge part having a tapered outer circumferential surface, thefirst pressure locking body is provided on an inner circumferentialsurface thereof with a first tapered seat part so as to correspond tothe tapered outer circumferential surface of the wedge part, and thesecond pressure locking body is movably engaged with the first threadsof the support rod through a screw-type engagement, and is provided onan inner circumferential surface thereof with a second tapered seat partso as to correspond to the tapered shoulder part of the support rod.

In still another aspect, the pressure locking unit may comprise apressure locking body, with at least one pair of first slits and atleast one pair of second slits formed in upper and lower ends of thepressure locking body such that the first and second slits are openupwards and downwards, respectively, wherein the pressure locking bodyis provided with annular-shaped first and second pressure parts aroundupper and lower edges thereof.

In still another aspect, the support rod may be provided with threadsformed around an outer circumferential surface thereof, a taperedshoulder part formed at a location above the threads, and a wedge partformed in a lower portion of the threads and having a tapered outercircumferential surface, the pressure locking body may be movablyengaged with the threads of the support rod through screw-typeengagement, and may be provided on a portion of the innercircumferential surface thereof having the first slits, with a firsttapered seat part so as to correspond to the tapered shoulder part ofthe support rod, and may be provided on another portion of the innercircumferential surface thereof having the second slits with a secondtapered seat part so as to be in contact with the tapered shoulder partof the wedge part.

In still another aspect, the locking mechanism for poles may furthercomprise: an elastic member provided on a lower end of the support rod.

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings. The technical terms and words used, both in the descriptionand in the claims, must not be interpreted according to their dictionarymeanings, but must be interpreted to have meanings or concepts pertinentto the scope and spirit of the invention, based on the principle bywhich the inventor can appropriately define the technical terms andwords to explain the invention in the best way.

Advantageous Effects

As described above, the locking mechanism for poles according to thepresent invention is advantageous in that it has two or more pressureparts spaced apart from each other in a longitudinal direction, thusrealizing a multiple pressurizing structure and causing pressure to acton two or more points at the junction between the pressure locking bodyand a unit shaft, and increasing the locking strength between two lockedunit shafts.

Further, in the present invention, the locking pressure of the pressurelocking body is applied to a unit shaft at longitudinally spaced points,so that the locking strength of the locking mechanism can be dispersedor distributed in a longitudinal direction, and the resistance of thetwo locked unit shafts against compressive force or tensile force actingin a longitudinal direction can be increased, and the two locked unitshafts can be prevented from suddenly slipping toward each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view illustrating a locking mechanismfor poles according to a first embodiment of the present invention;

FIG. 2 is a sectional view illustrating the assembled locking mechanisminserted into a unit shaft of a pole according to the first embodimentof the present invention;

FIG. 3 is a sectional view illustrating the locking operation of thelocking mechanism according to the first embodiment of the presentinvention;

FIG. 4 is an exploded perspective view illustrating a locking mechanismfor poles according to a second embodiment of the present invention;

FIG. 5 is a sectional view illustrating the assembled locking mechanisminserted into a unit shaft of a pole according to the second embodimentof the present invention;

FIG. 6 is a sectional view illustrating the locking operation of thelocking mechanism according to the second embodiment of the presentinvention;

FIG. 7 is an exploded perspective view illustrating a locking mechanismfor poles according to a third embodiment of the present invention;

FIG. 8 is a partially sectioned view of the assembled locking mechanism,taken along line A-A of FIG. 7;

FIG. 9 is a view taken along line A-A of FIG. 7, illustrating thelocking operation of the locking mechanism;

FIG. 10 is a view taken along line B-B of FIG. 7, illustrating thelocking operation of the locking mechanism;

FIG. 11 is an exploded perspective view illustrating a locking mechanismfor poles according to a fourth embodiment of the present invention;

FIG. 12 is a partially sectioned view of the assembled locking mechanismtaken along line C-C of FIG. 11;

FIG. 13 is a view taken along line C-C of FIG. 11, illustrating thelocking operation of the locking mechanism; and

FIG. 14 is a view taken along line D-D of FIG. 11, illustrating thelocking operation of the locking mechanism.

DESCRIPTION OF REFERENCE CHARACTERS OF IMPORTANT PARTS

11: support rod 12: pressure locking body

13: retainer 17: elastic member

51, 52: unit shafts

MODE FOR THE INVENTION

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings.

Hereinbelow, preferred embodiments of the present invention will bedescribed with reference to the accompanying drawings.

In the following description, it is to be noted that, wherever possible,the same reference numerals will be used throughout the drawings and thedescription to refer to the same or like parts. Further, when thefunctions of conventional elements and the detailed description ofelements related to the present invention may make the gist of thepresent invention unclear, a detailed description of those elements willbe omitted.

FIG. 1 through FIG. 3 are views illustrating a locking mechanism forpoles according to a first embodiment of the present invention. As shownin the drawings, the locking mechanism for poles according to the firstembodiment of the present invention is interposed between a pair of unitshafts 51 and 52 so as to releasably lock the two unit shafts togetherand comprises a support rod 11 and a pressure locking unit.

The support rod 11 is movably inserted into a first unit shaft 51 at afirst end thereof, and is fixed to a second unit shaft 52 at a secondend thereof.

The support rod 11 is provided with threads 11 a on part of the outersurface thereof. The support rod 11 further comprises a tapered shoulderpart 11 c, which has a gradually reduced diameter and is formed on theupper end of the threads 11 a, and a small-diameter tip part 11 b,formed on the upper end of the tapered shoulder part 11 c.

The pressure locking unit comprises a single pressure locking body 12having at least one pair of main slits 12 b. The pressure locking body12 is preferably made of an elastic material, such as metal, rubber orplastic material. The pair of main slits 12 b is longitudinally formedin the upper end of the pressure locking body 12 such that they arediametrically opposed to each other, and the pressure locking body 12can be elastically opened in opposite directions around the pair of mainslits 12 b.

Further, one pair of sub-slits 12 f is formed in the pressure lockingbody 12 at predetermined locations, which are angularly spaced apartfrom the pair of main slits 12 b at right angles, such that thesub-slits 12 f are diametrically opposed to each other. The sub-slits 12f are slit in a longitudinal direction opposite the slit direction ofthe main slits 12 b, so that the sub-slits 12 f promote the elasticopening action of the pressure locking body 12 around the main slits 12b.

Further, the pressure locking body 12 has threads 12 g in the innercircumferential surface of one end thereof, so as to be movably engagedwith the threads 11 a of the support rod 11 through screw-typeengagement. The upper end of the threads 12 g of the pressure lockingbody 12 is provided with a tapered seat part 12 a, which corresponds tothe tapered shoulder part 11 c of the support rod 11.

The pressure locking body 12 is provided on the upper edge thereof withan annular-shaped first pressure part 12 c, which is formed through, forexample, chamfering. An annular protrusion 12 d is formed around theouter circumferential surface of the pressure locking body 12 at alocation longitudinally spaced apart from the first pressure part 12 cby a predetermined distance. A second pressure part 12 e is formedaround the corner of the annular protrusion 12 d.

Further, as shown in FIG. 1, the pressure locking body 12 is provided onthe lower end thereof with an elastic member 17. The elastic member 17elastically biases the pressure locking body 12 in the longitudinaldirection at the junction between the two locked unit shafts 51 and 52.

The elastic member 17 is supported at the upper end thereof by aretainer 13, and is supported at the lower end thereof on the upper endof the second unit shaft 52. The retainer 13 is provided with threads onthe inner circumferential surface 13 a thereof. The innercircumferential surface 13 a, having the threads, is engaged with thelower end of the threads 11 a of the support rod 11, thus fixing theretainer 13 to the support rod 11.

The assembly of the locking mechanism for poles according to the firstembodiment of the present invention will be described in detailhereinbelow.

As shown in FIG. 2, the second unit shaft 52, having the support rod 11,is inserted into the first unit shaft 51 in the state in which thesecond end of the support rod 11 is locked to the second unit shaft 52.Thereafter, the second unit shaft 52 may be rotated while gripping thefirst unit shaft 51 with a hand, or the first unit shaft 51 may berotated while gripping the second unit shaft 52. Due to the relativerotation of the two unit shafts 51 and 52, the threads 11 a of thesupport rod 11 and the threads 12 g of the pressure locking body 12undergo screw movement relative to each other, so that the taperedshoulder part 11 c of the support rod 11 is advanced along the taperedseat part 12 a of the pressure locking body 12, as shown in FIG. 3, thusopening the pressure locking body 12 outwards in radial directionsaround the main slits 12 b. Thus, both the first pressure part 12 c andthe second pressure part 12 e of the pressure locking body 12 arepressed onto the inner circumferential surface of the first unit shaft51 outwards in the radial directions, so that the pair of unit shafts 51and 52 can be securely locked together.

Therefore, the present invention provides a multiple pressurizingstructure using the first and second pressure parts 12 c and 12 e of thepressure locking body 12, thus realizing a structural advantage in whichthe pair of unit shafts 51 and 52 can be securely locked together.

Further, in the present invention, the pressure from the pressurelocking body 12 is imposed on the inner circumferential surface of theunit shaft 51 at longitudinally spaced points, so that the lockingstrength, realized by the pressure locking body 12, is dispersed ordistributed in a longitudinal direction. Thus, the present invention isadvantageous in that the resistance of the two locked unit shafts 51 and52 against both the compressive force and the tensile force, acting inlongitudinal directions, can be increased, and the locked unit shafts 51and 52 can be prevented from suddenly slipping toward each other.

In addition, when it is required to release or separate the two lockedunit shafts 51 and 52 from each other, either unit shaft 51 or 52 isrotated in a direction opposite the direction of the above-mentionedlocking process. Thus, the pressure locking body 12 executes screwmovement relative to the threads 11 b of the support rod 11 in theopposite direction, so that the opened pressure locking body 12 isclosed around the main slits 12 b and allows a user to easily release orseparate the two locked unit shafts 51 and 52 from each other.

FIG. 4 and FIG. 5 illustrate a locking mechanism for poles according toa second embodiment of the present invention. As shown in FIGS. 4 and 5,the locking mechanism for poles according to the second embodiment ofthe present invention is interposed between two locked unit shafts 51and 52, and comprises a support rod 11 and a pressure locking unit.

The support rod 11 is movably inserted at a first end thereof into thefirst unit shaft 51, and is fixed to the second unit shaft 52 at asecond end thereof.

The support rod 11 is provided with first threads 11 a on part of theouter surface thereof. The support rod 11 further comprises a taperedshoulder part 11 c, which has a gradually reduced diameter and is formedon the upper end of the first threads 11 a. A small-diameter tip part 11b, having a diameter smaller than that of the threads 11 a, is formed onthe upper end of the tapered shoulder part 11 c, with second threads 11d formed around part of the small-diameter tip part 11 b.

In the second embodiment, the pressure locking unit further comprisesfirst and second pressure locking bodies 22 and 23, which are movablyengaged with the support rod 11 through screw-type engagement.

The first pressure locking body 22 is preferably made of an elasticmaterial, such as metal, rubber or plastic material. A pair of mainslits 22 b is longitudinally formed in the lower end of the firstpressure locking body 22 such that they are diametrically opposed toeach other, and the first pressure locking body 22 can be elasticallyopened in opposite directions around the pair of main slits 22 b.Further, a mounting slot 22 e is formed in the first pressure lockingbody 22 at a position above the main slits 22 b, with a nut 25 fitted inthe mounting slot 22 e so as to be movably engaged with the secondthreads 11 d of the support rod 11 through a screw-type engagement.

Further, one pair of sub-slits (not shown) is formed in the firstpressure locking body 22 at predetermined locations, which are angularlyspaced apart from the pair of main slits 22 b at right angles, such thatthe sub-slits are diametrically opposed to each other. The sub-slits areslit in a longitudinal direction opposite the slit direction of the mainslits 22 b, so that the sub-slits promote the elastic opening action ofthe first pressure locking body 22 around the main slits 22 b.

The first pressure locking body 22 is provided on the lower edge thereofwith an annular-shaped first pressure part 22 c, which is formedthrough, for example, chamfering. The first pressure locking body 22 isprovided on the upper inner circumferential surface thereof with threads22 a so as to be movably engaged with the second threads 11 d of thesupport rod 11 through screw-type engagement. A first tapered seat part22 d is provided in the first pressure locking body 22 at a locationbeneath the threads 22 a so as to be in contact with and move relativeto the outer circumferential surface of a wedge part 24, which will bedescribed in detail later herein.

The wedge part 24 is a tapered body, the diameter of which is graduallyreduced in an upward direction. The tapered outer circumferentialsurface of the wedge part 24 is in contact with the first tapered seatpart 22 d of the first pressure locking body 22. The lower surface ofthe wedge part 24 is supported by a washer 26, which is fastened to thelower end of the second threads 11 d of the support rod 11.

In other words, when the first tapered seat part 22 d of the firstpressure locking body 22 is moved relative to the outer circumferentialsurface of the wedge part 24 while being in contact therewith, the firstpressure locking body 22 is opened around the slits 22 b, so that thefirst pressure part 22 c is pressed onto the inner circumferentialsurface of the first unit shaft 51.

The second pressure locking body 23 is preferably made of an elasticmaterial, such as metal, rubber or plastic material. A pair of mainslits 23 b is longitudinally formed in the upper end of the firstpressure locking body 23 such that they are diametrically opposed toeach other, and the second pressure locking body 23 can be elasticallyopened in opposite directions around the pair of main slits 23 b.

Further, one pair of sub-slits 23 f is formed in the second pressurelocking body 23 at predetermined locations, which are angularly spacedapart from the pair of main slits 23 b at right angles, such that thesub-slits 23 f are diametrically opposed to each other. The sub-slits 23f are slit in a longitudinal direction, opposite the slit direction ofthe main slits 23 b, so that the sub-slits 23 f promote the elasticopening action of the second pressure locking body 23 around the mainslits 23 b.

The second pressure locking body 23 is provided on the innercircumferential surface thereof with threads 23 g, so as to be movablyengaged with the first threads 11 a of the support rod 11. A secondtapered seat part 23 a is provided in the second pressure locking body23 at a position above the threads 23 g, so as to correspond to thetapered shoulder part 11 c of the support rod 11.

The second pressure locking body 23 may be is provided on the upper edgethereof with an annular-shaped second pressure part 23 c, which isformed through, for example, chamfering.

When the two unit shafts 51 and 52, having the locking mechanismaccording to the second embodiment, are rotated relative to each otherin the same manner as that described for the first embodiment, thetapered shoulder part 11 c of the support rod 11 moves longitudinallyrelative to the second tapered seat part 23 a of the second pressurelocking body 23 due to relative rotation between the threads 23 g of thesecond pressure locking body 23 and the first threads 11 b of thesupport rod 11. Thus, the second pressure locking body 23 is openedaround the main slits 23 a, so that the second pressure part 23 c ispressed onto the inner circumferential surface of the first unit shaft51, as shown in FIG. 6. In the above state, the first tapered seat part22 d of the first pressure locking body 22 moves relative to the taperedouter circumferential surface of the wedge part 24 while being insurface contact therewith, so that the first pressure locking body 22 isopened around the main slits 22 b until the first pressure part 22 c ispressed onto the inner circumferential surface of the first unit shaft51. Thus, the two unit shafts 51 and 52 are locked together.

The construction and operation of the locking mechanism according to thesecond embodiment, except for the above-mentioned construction andoperation, remain the same as those of the first embodiment, and furtherexplanation is thus deemed unnecessary.

FIG. 7 through FIG. 9 illustrate a locking mechanism for poles accordingto a third embodiment of the present invention. As shown in FIGS. 7through 9, the locking mechanism according to the third embodiment ofthe present invention is interposed between two locked unit shafts 51and 52, and comprises a support rod 11 and a pressure locking unit.

The support rod 11 is movably inserted into a first unit shaft 51 at afirst end thereof, and is fixed to a second unit shaft 52 at a secondend thereof.

The support rod 11 is provided with threads 11 a on part of the outersurface thereof. The support rod 11 further comprises a tapered shoulderpart 11 c, which has a gradually reduced diameter and is formed on theupper end of the threads 11 a, and a small-diameter tip part 11 b,formed on the upper end of the tapered shoulder part 11 c.

The pressure locking unit according to the third embodiment comprises apressure locking body 31, with a pair of first slits 31 a and a pair ofsecond slits 31 b formed in opposite ends of the pressure locking body31 so as to be open upwards and downwards, respectively.

In the present invention, the first and second slits 31 a and 31 b maybe formed on the opposite ends of the pressure locking body 31 such thatthey are circumferentially offset from each other on the pressurelocking body 31 (in FIG. 7, the first and second slits 31 a and 31 b areoffset from each other so as to be perpendicular to each other).

Alternatively, the first and second slits 31 a and 31 b may be formed onthe opposite ends of the pressure locking body 31 such that they arearranged in the same axial plane.

Further, each of the first and second pairs of slits 31 a and 31 b isformed on the pressure locking body 31 such that each pair of slitsfaces each other in the same manner as that described for the first andsecond embodiments.

The pressure locking body 31 according to the third embodiment mayfurther comprise first and second sub-slits (not shown), which areformed on the pressure locking body 31 at locations angularly spacedapart from the first and second slits 31 a and 31 b at right angles. Thefirst and second sub-slits (not shown) of the third embodiment mayexecute the same function as in the first and second embodiments.

As shown in FIG. 8, the pressure locking body 31 is provided, on theinner circumferential surface thereof in a predetermined portion havingthe first slits 31 a, with a first tapered seat part 31 c so as tocorrespond to the tapered shoulder part 11 c of the support rod 11.Further, the first tapered seat part 31 c is provided, on the lowerinner circumferential surface thereof, with threads 31 g so as to bemovably engaged with the threads 11 a of the support rod 11 throughscrew-type engagement.

As shown in FIG. 10, the pressure locking body 31 is also provided, onthe inner circumferential surface thereof at another predeterminedportion having the second slits 31 b, with a second tapered seat part 31f, which is in contact with the tapered outer circumferential surface ofthe wedge part 34. Further, a mounting slot 31 h is formed in thepressure locking body 31 at a position above the second slits 31 b witha nut 35 fitted in the mounting slot 31 h so as to be movably engagedwith the threads 11 a of the support rod 11 through screw-typeengagement.

The lower end of the wedge part 34 may be supported by a washer 36,which is fastened to the threads 11 a of the support rod 11.

Further, the pressure locking body 31 is provided on the upper and loweredges thereof with first and second annular-shaped pressure parts 31 dand 31 e, which are formed through, for example, chamfering.

When the pair of unit shafts 51 and 52 of the locking mechanismaccording to the third embodiment is rotated relative to each other inthe same manner as those of the first and second embodiments, thethreads 31 g of the pressure locking body 31 and the threads 11 a of thesupport rod 11 are rotated relative to each other, so that the upperportion of the pressure locking body 31 is opened around the first slits31 a due to relative movement between the first tapered seat part 31 cof the pressure locking body 31 and the tapered shoulder part 11 c ofthe support rod 11. Thus, the first pressure part 31 d of the pressurelocking body 31 is pressed onto a portion of the inner circumferentialsurface of the first unit shaft 51, as shown in FIG. 9. Further, thelower portion of the pressure locking body 31 is opened around the slotslits 31 b due to relative movement between the second tapered seat part31 f and the wedge part 34. Thus, the second pressure part 31 e of thepressure locking body 31 is pressed onto another portion of the innercircumferential surface of the first unit shaft 51, as shown in FIG. 10,thus securely locking the two unit shafts 51 and 52 to each other.

The construction and operation of the locking mechanism according to thethird embodiment, except for the above-mentioned construction andoperation, remain the same as those of the first and second embodiments,and further explanation is thus deemed unnecessary.

FIG. 11 through FIG. 14 illustrate a locking mechanism for polesaccording to a fourth embodiment of the present invention. As shown inFIGS. 11 through 14, the locking mechanism according to the fourthembodiment of the present invention is interposed between two lockedunit shafts 51 and 52, and comprises a support rod 11 and a pressurelocking unit.

The support rod 11 is movably inserted into a first unit shaft 51 at afirst end thereof, and is fixed to a second unit shaft 52 at a secondend thereof.

The support rod 11 is provided with threads 11 a on part of the outersurface thereof. The support rod 11 further comprises a first taperedshoulder part 11 c, which has an upwardly gradually reduced diameter andis formed on an upper end of the threads 11 a, and a second taperedshoulder part 11 e, which has a downwardly gradually increased diameterand is formed beneath the lower end of the threads 11 a. The secondtapered shoulder part 11 e is externally threaded. Further, asmall-diameter tip part 11 b is formed on the upper end of the taperedshoulder part 11 c.

The pressure locking unit according to the fourth embodiment comprises asingle pressure locking body 42 having a first pair of slits 42 b and asecond pair of slits 42 f.

The single pressure locking body 42 is preferably made of an elasticmaterial, such as metal, rubber or plastic material. The pair of firstslits 42 b is longitudinally formed in the upper end of the pressurelocking body 42 such that they are diametrically opposed to each other,and the pressure locking body 42 can be elastically opened in oppositedirections around the pair of first slits 42 b, as shown in FIG. 13.

Further, the pair of second slits 42 f is open in a direction oppositethe opening direction of the first slits 42 b, and is angularly spacedapart from the first slits 42 b at a right angle. The lower part of thepressure locking body 42 can be elastically opened in oppositedirections around the second slits 42 f, as shown in FIG. 14.

The pressure locking body 42 is provided on the first innercircumferential surface thereof with threads 42 g so as to be movablyengaged with the threads 11 a of the support rod 11. A tapered seat part42 a is formed in the pressure locking body 42 at a position above thethreads 42 g so as to correspond to the first tapered shoulder part 11 cof the support rod 11.

The pressure locking body 42 is provided on the upper edge thereof withan annular-shaped first pressure part 42 c, which is formed through, forexample, chamfering. An annular protrusion 42 d is formed around theouter circumferential surface of the pressure locking body 42 at aposition spaced apart from the first pressure part 42 c by apredetermined distance. A second pressure part 42 e is formed around anedge of the annular protrusion 42 d.

Further, the lower edge of the pressure locking body 42 is provided withan annular-shaped third pressure part 42 k. An annular-shaped fourthpressure part 42 j is formed around the pressure locking body 42 at aposition upwardly spaced apart from the third pressure part 42 k by apredetermined distance.

The assembly of the locking mechanism for poles according to the fourthembodiment of the present invention will be described in detailhereinbelow.

The second unit shaft 52, having the support rod 11, is inserted intothe first unit shaft 51, as shown in FIG. 12, in a state in which thesecond end of the support rod 11 is locked to the second unit shaft 52.Thereafter, the second unit shaft 52 may be rotated while gripping thefirst unit shaft 51 in the hand, or the first unit shaft 51 may berotated while gripping the second unit shaft 52. Due to the relativerotation of the two unit shafts 51 and 52, the threads 11 a of thesupport rod 11 and the threads 42 g of the pressure locking body 42undergo screw movement relative to each other.

Thus, the first tapered shoulder part 11 c of the support rod 11 isadvanced along the tapered seat part 42 a of the pressure locking body42, as shown in FIG. 13, thus opening the upper part of the pressurelocking body 42 outwards in radial directions around the first slits 42b. Therefore, both the first pressure part 42 c and the second pressurepart 42 e of the pressure locking body 42 are pressed onto the innercircumferential surface of the first unit shaft 51 outwards in radialdirections.

In the same time, the second tapered shoulder part 11 e of the supportrod 11 is moved relative to the lower inner circumferential surface ofthe pressure locking body 42, as shown in FIG. 14, thus opening thelower part of the pressure locking body 42 in opposite directions aroundthe second slits 42 f. Therefore, the third and fourth pressure parts 42k and 42 j of the pressure locking body 42 are pressed onto the innercircumferential surface of the first unit shaft 51 outwards in radialdirections.

Briefly described, the locking mechanism for poles according to thefourth embodiment of the present invention is advantageous in that itcan securely lock the two unit shafts 51 and 52 together using amultiple pressurizing structure, realized by the first through fourthpressure parts 42 c, 42 e, 42 k and 42 j of the pressure locking body42.

As described above, the pressure locking body 12, 22, 23, 31, 42according to the present invention comprises two or more pressure parts12 c, 12 e, 22 c, 23 c, 31 d, 31 e, 42 c, 42 e, 42 k, 42 j, which arespaced apart from each other in a longitudinal direction, thus having amultiple pressurizing structure or a multiple contact support structure.Therefore, locking pressure or frictional contact locking force acts atthe junction between the pressure locking body and the first unit shaftat two or more points, thus increasing the frictional force between thepressure locking body and the first unit shaft and increasing thelocking strength between the two locked unit shafts 51 and 52.

Further, the present invention is advantageous in that the lockingpressure of the pressure locking body is applied to a unit shaft atlongitudinally spaced points, so that the locking strength of thelocking mechanism can be dispersed or distributed in a longitudinaldirection, and the resistance of the two locked unit shafts againstcompressive force or tensile force acting in a longitudinal directioncan be increased, and the two locked unit shafts can be prevented fromsuddenly slipping toward each other.

Although the embodiments of the present invention have been disclosedfor illustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention as disclosed in theaccompanying claims.

1. A locking mechanism for poles, comprising: a support rod insertedinto a first unit shaft at a first end thereof and locked to a secondunit shaft at a second end thereof, with threads formed around part ofan outer circumferential surface of the support rod; and a pressurelocking unit movably engaged with the threads of the support rod throughscrew-type engagement, with at least one pair of longitudinal slitsformed in the pressure locking body such that the slits are open in onedirection, and with two or more pressure parts formed in the pressurelocking body in a longitudinal direction, wherein the pressure lockingunit comprises: a pressure locking body having a pair of first slits anda pair of second slits, which are formed in the pressure locking bodysuch that the first and second slits are angularly spaced apart fromeach other at right angles, wherein the pressure locking body comprises:an annular-shaped first pressure part formed around a first edge of thepressure locking body and an annular-shaped second pressure part spacedapart from the first pressure part; and an annular-shaped third pressurepart formed around a second edge of the pressure locking body and anannular-shaped fourth pressure part spaced apart from the third pressurepart, wherein the first and second slits are opened in oppositedirections, the support rod is provided both with a first taperedshoulder part at a location near a first end of the threads and with asecond tapered shoulder part at a location near a second end of thethreads, and the pressure locking body is provided on an innercircumferential surface thereof with a tapered seat part so as tocorrespond to the first tapered shoulder part of the support rod.